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Changes in the Ca 2+ ‐Transport Processes of Red Cells during Cold Storage in ACD
Author(s) -
Szász I.,
Sarkadi B.,
Gárdos G.
Publication year - 1978
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1978.tb03626.x
Subject(s) - chemistry , calcium , ionophore , biophysics , lanthanum , membrane transport , biochemistry , inorganic chemistry , membrane , biology , organic chemistry
In order to characterize Ca 2+ ‐transport in red cells stored in ACD Ca 2+ ‐loading and Mg 2+ ‐depletion by the ionophore A23187, CaATPase activity determination in intact cells and an accurate Ca 2+ ‐influx technique were adapted to preserved blood. Active Ca 2+ ‐efflux (pump) was measured in rejuvenated cells loaded by Ca 2+ with A23187. The rate of Ca 2+ ‐pump declined only slightly during 3 weeks of storage (from 80 ± 15 to 66 ± 17 μmoles Ca 2+ /l. cells/min) and a marginal trend of decrease in the Ca:ATP ratio was observed (from 1.96 ± 0.15 to 1.88±0.11). Passive Ca 2+ ‐influx (leak) was studied in regenerated cells in which the Ca 2+ ‐pump was blocked with 0.2 mm lanthanum. Ca 2+ ‐influx showed a slow increase during the first 3 weeks of storage (from 0.4±0.16 to 1.25±0.4 μmoles Ca 2+ /l. cells/min), later it increased rapidly. Passive Ca 2+ leak and exchange transport were studied in unregenerated, phosphate ester‐depleted cells. In this case passive Ca 2+ ‐influx increased 2–3‐fold as early as 1–2 d after storage in ACD. This initial increase was followed by a continuous slow enhancement that reached a flux of 3.5±0.7 μmoles Ca 2+ /l. cells/min after 3 weeks of storage. The passive Ca 2+ ‐permeability increase that occurred during storage could be readily compensated by the Ca 2+ ‐pump without causing metabolic imbalance. The Ca 2+ ‐transport, of unregenerated stored cells, however, showed impairment under certain conditions (A23187+EDTA and lanthanum treatments, ghost preparation). The Ca 2+ ‐induced shape changes were reversible and ran parallel with the cell Ca 2+ level during Ca 2+ ‐pumping up to 5 weeks of storage. This finding indicates a direct relationship between cell Ca 2+ and shape.